[Intel-gfx] [PATCH v7 3/4] drm/i915: Clean steer semaphore on resume

[Nirmoy Das]

During resume, the steer semaphore on GT1 was observed to be held. The
hardware team has confirmed the safety of clearing steer semaphores
for all GTs during driver load/resume, as no lock acquisitions can occur
in this process by other agents.

v2: reset on resume not in intel_gt_init().
v3: do the reset on intel_gt_resume_early()
v4: do general sanitization for all GTs(Matt)

Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com>
---
 drivers/gpu/drm/i915/gt/intel_gt_pm.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
index dab73980c9f1..3461f3e74277 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.c
@@ -13,6 +13,7 @@
 #include "intel_engine_pm.h"
 #include "intel_gt.h"
 #include "intel_gt_clock_utils.h"
+#include "intel_gt_mcr.h"
 #include "intel_gt_pm.h"
 #include "intel_gt_print.h"
 #include "intel_gt_requests.h"
@@ -218,6 +219,15 @@ void intel_gt_pm_fini(struct intel_gt *gt)
 
 void intel_gt_resume_early(struct intel_gt *gt)
 {
+	/*
+	 * Sanitize steer semaphores during driver resume. This is necessary
+	 * to address observed cases of steer semaphores being
+	 * held after a suspend operation. Confirmation from the hardware team
+	 * assures the safety of this operation, as no lock acquisitions
+	 * by other agents occur during driver load/resume process.
+	 */
+	intel_gt_mcr_lock_sanitize(gt);
+
 	intel_uncore_resume_early(gt->uncore);
 	intel_gt_check_and_clear_faults(gt);
 }
-- 
2.41.0